JP3819570B2

JP3819570B2 - Cylindrical alkaline storage battery using non-sintered electrodes

Info

Publication number: JP3819570B2
Application number: JP31749297A
Authority: JP
Inventors: 茂人為実; 隆明池町; 貴志山口; 訓生川
Original assignee: Sanyo Electric Co Ltd
Current assignee: Sanyo Electric Co Ltd
Priority date: 1997-11-18
Filing date: 1997-11-18
Publication date: 2006-09-13
Anticipated expiration: 2017-11-18
Also published as: TW419849B; JPH11149914A; EP0917221A1; CN1121079C; HK1020637A1; DE69819111D1; EP0917221B1; HK1020113A1; CN1217589A; DE69819111T2; US6187473B1

Description

【０００１】
【発明の属する技術分野】
本発明はニッケル・水素蓄電池、ニッケル・カドミウム蓄電池、ニッケル・亜鉛蓄電池などのアルカリ蓄電池に係り、特に、活物質保持体に活物質を塗着した電極と集電体との導電接続に関する。
【０００２】
【従来の技術】
従来、ニッケル・カドミウム蓄電池、ニッケル・水素蓄電池、ニッケル・亜鉛蓄電池などのアルカリ蓄電池に使用される電極は、パンチングメタル等の芯体にニッケル粉末を焼結して形成した焼結基板にニッケル塩、カドミウム塩等の溶液を含浸し、アルカリ処理により活物質化するいわゆる焼結式電極が知られている。この焼結式電極は、焼結基板を高多孔度とした場合には機械的強度が弱くなるため、実用的には８０％程度の多孔度とするのが限界であるとともに、パンチングメタル等の芯体を必要とすることから、活物質の充填密度が低く、高エネルギー密度の電極を実現する上で問題がある。また、焼結基板の細孔は１０μｍ以下であるので、活物質の充填工程を何度も繰り返す必要がある溶液含浸法や電着含浸法に限定されるため、充填工程が煩雑であるとともに製造コストも高くなるという問題がある。
【０００３】
一方、これらの欠点を改良するために、金属繊維焼結体や発泡ニッケル（ニッケルスポンジ）などの三次元的な網目構造をもった金属多孔体（活物質保持体）にペースト状活物質を直接充填した、いわゆる非焼結式電極が主流となってきた。この種の三次元的な網目構造をもった金属多孔体は、その多孔度が約９５％と高多孔度であるので、活物質を高密度に充填できる。そのため、高容量の電池が得られるようになるとともに、この種の非焼結式電極は活物質をそのまま金属多孔体に充填するので、面倒な活物質化の処理が必要でなくなり、製造が容易になるという利点がある。
【０００４】
ところで、この種の非焼結式電極においては、三次元的な網目構造をもった金属多孔体は芯体を有していないため、この金属多孔体に活物質を充填して形成した電極と電池端子との間の導電接続に種々の提案がなされている。例えば、特開昭６１−２１８０６７号公報においては、金属繊維のフェルト状焼結体（金属繊維焼結体）を電極支持体とする電極を製造するに際して、金属繊維のフェルト状体と、網状体、パンチングメタル、線材、平板などからなる導電補助体とを焼結により一体的に形成して、金属繊維のフェルト状体の機械的強度を向上させるとともに、集電性を改良することが提案された。
【０００５】
しかしながら、金属繊維焼結体は細い金属繊維（例えば、線経が１０μｍ）を電極の長さ方向に束ねて長尺状に形成されているため、この金属繊維焼結体に活物質を塗着した後、セパレータを介して正・負極を渦巻状に巻回すると、巻回時に細い金属繊維が切断されて、この切断された繊維片がセパレータを突き破って正・負極間が電気的に接続され、内部短絡が発生するという問題を生じる。
【０００６】
一方、発泡ニッケルを電極支持体とする電極においては、発泡ニッケルに活物質を塗着した後、セパレータを介して正・負極を渦巻状に巻回しても発泡ニッケル自体が切断されるということがない。しかしながら、電極からの集電のため、この電極の一部の活物質を剥離して発泡ニッケルを露出させ、この露出部に舌片状集電タブを溶接するようにしている。このため、舌片状集電タブでの集電性が良好でないので、大電流放電を行うと集電タブで電圧降下を生じるという問題を生じた。
【０００７】
そこで、特開昭６２−１３９２５１号公報において、発泡ニッケルを電極支持体とする電極の端部を幅方向に圧縮して密な層を形成し、この圧縮した密な層と電極面に垂直に配置された円板状リード片とを溶接した、いわゆるタブレス方式の電池が提案された。この特開昭６２−１３９２５１号公報において提案された電極にあっては、発泡メタルを電極支持体とするため、渦巻状に巻回しても発泡メタル自体が切断されるということがないとともに、電極の端部と円板状リード片とを溶接しているので集電性が向上する。
【０００８】
【発明が解決しようとする課題】
しかしながら、特開昭６２−１３９２５１号公報において提案された電極にあっては、電極の端部を幅方向に圧縮して形成した密な層は柔軟性が劣るため、セパレータを介して正・負極を巻回する際に密な層の一部が破断してバリが生じ、このバリがセパレータを突き破って内部短絡が発生するという問題を生じる。また、電極全体として柔軟な部分と柔軟ではない部分が混在すると、正・負極を一様な圧力で巻回することが難しいため、これらを巻回して電極体とした場合に均一な圧力が付加されないという問題も生じる。
【０００９】
また、発泡ニッケルからなる電極支持体の端部一面に活物質の未充填部分を形成し、この活物質未充填部分にリボン状の金属板を溶着して電極とすることも考えられる。しかしながら、このようにして形成した電極と対極とをセパレータを介して渦巻状に巻回すると、リボン状の金属板は柔軟性を有さないため、リボン状の金属板の一部が角状に折れ曲がって対極と接触して内部短絡を生じるという問題を生じる。
【００１０】
本発明の目的は、上記の問題を解消するため、三次元的な網目構造をもった金属多孔体を活物質保持体として用いて渦巻状に巻回しても、内部短絡を生ずることなく良好に集電できる電極体を得ることにある。
【００１１】
【課題を解決するための手段およびその作用・効果】
本発明は、上記の目的を達成するため、発泡ニッケルからなる三次元的に網目構造をもった活物質保持体にペースト状活物質を保持した一方極の非燒結電極と他方極の電極とをセパレータを介して渦巻状に巻回した電極体を、前記一方極の非燒結電極の上辺部に集電体の略円板状集電部を接続した状態にて、前記他方極の端子を兼ねる円筒状金属外装缶に収納した円筒状アルカリ蓄電池であって、前記集電体の略円板状集電部に接続される前記非燒結電極の上辺部がその表面に保持されたペースト状活物質を剥離して圧縮により薄肉に形成された活物質未充填部分であって、この活物質未充填部分の表面に溶着した孔径が０．３０−１．００ｍｍの孔を一行毎に互い違いになるように多数形成した多孔性金属板をその切断部位に突出する各孔の切断端面にて前記集電体の略円板状集電部に溶着したことを特徴とする非焼結電極を用いた円筒状アルカリ蓄電池を提供するものである。
【００１２】
多孔性の金属板は柔軟性を有するため、このような柔軟性を有する多孔性の金属板を活物質未充填部分に溶着して渦巻状に巻回しても、多孔性の金属板が破断するようなことはない。このため、電極体内に内部短絡を生ずることがなくなり、電極体の多孔性金属板と略円板状集電部とが接続されて良好に集電できるようになって、大電流放電が可能なアルカリ蓄電池を得ることができるようになる。そして、三次元的に網目構造をもった活物質保持体を発泡ニッケルにすると、発泡ニッケルは柔軟性を有するため、渦巻状に巻回しても発泡ニッケル自体が切断されるということがない。このため、電極体内に内部短絡を生ずることなく、集電性が良好で大容量のアルカリ蓄電池を得ることができるようになる。
【００１３】
また、多孔性の金属板としてパンチングメタルあるいはエキスパンドメタルを用いるようにすると、これらのパンチングメタルあるいはエキスパンドメタルは充分な柔軟性を有するため、渦巻状に巻回しても、パンチングメタルあるいはエキスパンドメタルが破断するようなことはない。また、パンチングメタルあるいはエキスパンドメタルは孔部の中央部で切断されており、かつ切断部が略円板状集電部と溶接されていると、この切断部は略円板状集電部に対して突起状に接触することとなるため、抵抗溶接を行うとこの突起状に接触している部分の電流密度が増大して強固に固着されるようになる。
【００１９】
【発明の実施の形態】
以下に、本発明の非焼結電極を用いた円筒状アルカリ蓄電池をニッケル−水素蓄電池に適用した場合の一実施の形態を図に基づいて説明する。
なお、図１は発泡ニッケルからなる活物質保持体の活物質未充填部分に本実施形態の多孔性金属板を溶接した状態を示す図であり、図２は比較例（従来例）の金属板（リボン）を発泡ニッケルからなる活物質保持体の活物質未充填部分に溶接した状態を示す図であり、図３は他の比較例（従来例）の舌片状の集電タブを発泡ニッケルからなる活物質保持体の活物質未充填部分に溶接した状態を示す図であり、図４は図１の電極を渦巻状に巻回して形成した電極体を金属製の外装缶に収納した状態を破断して示す斜視図であり、図５は正極集電板を示す斜視図である。
【００２０】
１．ニッケル正極板の作製
ａ．実施例１
水酸化ニッケル９０重量部と、金属コバルト粉末５重量部と、水酸化コバルト粉末５重量部とを混合し、これをメチルセルロース１重量％水溶液２０重量部とを混練してペースト状活物質を作製する。このようにして作製したペースト状活物質１１を、基体目付が６００ｇ／ｍ²（なお、基体目付は４００〜７００ｇ／ｍ²の間で使用可能である）で厚みが１．５ｍｍであるニッケル発泡体（ニッケルスポンジ）からなる活物質保持体１０に充填する。なお、圧延後の活物質充填密度が約２．９〜３．０５ｇ／ｃｃ−ｖｏｉｄとなるようにペースト状活物質を充填する。ついで、ペースト状活物質１１を充填した活物質保持体１０を乾燥させた後、厚みが約０．７ｍｍになるまで圧延する。
【００２１】
ついで、このようにペースト状活物質１１を充填した活物質保持体１０の上辺部１２に図示しない超音波ホーンを押し当てて、上辺部１２に垂直方向に超音波振動を加えて、活物質保持体１０の上辺部１２に充填された活物質１１を活物質保持体１０より脱落させて剥離部を形成する。このとき、超音波ホーンを押し当てて超音波振動を与えることにより、上辺部１２は圧縮されて薄肉部となる。
【００２２】
一方、図１に示すように、多孔性金属板として、厚みが０．０６ｍｍで、孔径が０．３０〜１．００ｍｍの円孔を１行毎に互い違いとなるように多数形成して多孔度が２０〜６０％となるように形成したニッケル金属製のリボン状パンチングメタル１３を用いる。このニッケル金属製のリボン状パンチングメタル１３は幅が１．５ｍｍとなるように円孔の中心部で切断されている。
【００２３】
そして、このニッケル金属製のリボン状パンチングメタル１３を活物質保持体１０の剥離部に円孔の中心で切断された切断部が活物質保持体１０の上端部より若干突出するようにして載置し、直径１．５ｍｍの銅製の溶接棒を用いて２ｍｍ間隔で抵抗溶接を行い、実施例１のニッケル正極板１０ａを作製する。これにより、活物質保持体１０の上端部はパンチングメタル１３の切断部の一部が突起状に活物質保持体１０より突出することとなる。
【００２４】
ｂ．実施例２
実施例１と同様にして作成したペースト状活物質１１を実施例１と同様の活物質保持体１０に充填した後、この活物質保持体１０の上辺部１２に図示しない超音波ホーンを押し当てて、上辺部１２に垂直方向に超音波振動を加えて、活物質保持体１０の上辺部１２に充填された活物質１１を活物質保持体１０より脱落させて剥離部を形成する。このとき、超音波ホーンを押し当てて超音波振動を与えることにより、上辺部１２は圧縮されて薄肉部となる。
【００２５】
一方、図１に示すように、多孔性金属板として、厚みが０．１０ｍｍで、孔径が０．３０〜１．００ｍｍの円孔を１行毎に互い違いとなるように多数形成して多孔度が２０〜６０％となるように形成したニッケル金属製のリボン状パンチングメタル１４を用いる。このニッケル金属製のリボン状パンチングメタル１４は幅が１．５ｍｍとなるように孔の中心部で切断されている。
【００２６】
そして、このニッケル金属製のリボン状パンチングメタル１４を活物質保持体１０の剥離部に円孔の中心で切断された切断部が活物質保持体１０の上端部より若干突出するようにして載置し、直径１．５ｍｍの銅製の溶接棒を用いて２ｍｍ間隔で抵抗溶接を行い、実施例２のニッケル正極板１０ｂを作製する。これにより、活物質保持体１０の上端部はパンチングメタル１４の切断部の一部が突起状に活物質保持体１０より突出することとなる。
【００２７】
ｃ．実施例３
実施例１と同様にして作成したペースト状活物質１１を実施例１と同様の活物質保持体１０に充填した後、この活物質保持体１０の上辺部１２に図示しない超音波ホーンを押し当てて、上辺部１２に垂直方向に超音波振動を加えて、活物質保持体１０の上辺部１２に充填された活物質１１を活物質保持体１０より脱落させて剥離部を形成する。このとき、超音波ホーンを押し当てて超音波振動を与えることにより、上辺部１２は圧縮されて薄肉部となる。
【００２８】
一方、図１に示すように、多孔性金属板としては、厚みが０．１８ｍｍで、孔径が０．３０〜１．００ｍｍの孔を１行毎に互い違いとなるように多数形成して多孔度が２０〜６０％となるように形成したニッケル金属製のリボン状パンチングメタル１５を用いる。このニッケル金属製のリボン状パンチングメタル１５は幅が１．５ｍｍとなるように円孔の中心部で切断されている。
【００２９】
そして、このニッケル金属製のリボン状パンチングメタル１５を活物質保持体１０の剥離部に円孔の中心で切断された切断部が活物質保持体１０の上端部より若干突出するようにして載置し、直径１．５ｍｍの銅製の溶接棒を用いて２ｍｍ間隔で抵抗溶接を行い、実施例３のニッケル正極板１０ｃを作製する。これにより、活物質保持体１０の上端部はパンチングメタル１５の切断部の一部が突起状に活物質保持体１０より突出することとなる。
【００３０】
ｄ．比較例１
図２に示すように、実施例１と同様にして作成したペースト状活物質２１を実施例１と同様の活物質保持体２０に充填した後、この活物質保持体２０の上辺部２２に図示しない超音波ホーンを押し当てて、上辺部２２に垂直方向に超音波振動を加えて、活物質保持体２０の上辺部２２に充填された活物質２１を活物質保持体２０より脱落させて剥離部を形成する。このとき、超音波ホーンを押し当てて超音波振動を与えることにより、上辺部２２は圧縮されて薄肉部となる。
【００３１】
一方、図２に示すように、金属板としては、厚みが０．１０ｍｍで幅が１．５ｍｍになるように切断したニッケル金属製の金属板（リボン状メタル）２３を用意し、このニッケル金属製のリボン状メタル２３を活物質保持体２０の剥離部に載置し、直径１．５ｍｍの銅製の溶接棒を用いて２ｍｍ間隔で抵抗溶接を行い、比較例１のニッケル正極板２０ａを作製する。
【００３２】
ｅ．比較例２
図３に示すように、実施例１と同様にして作成したペースト状活物質３１を実施例１と同様の活物質保持体３０に充填した後、この活物質保持体３０の中央上部の一部３２にこの一部３２と同幅の超音波ホーンを押し当てて、中央上部に垂直方向に超音波振動を加えて、活物質保持体３０の中央上部の一部３２に充填された活物質３１を活物質保持体３０より脱落させて剥離部を形成する。このとき、超音波ホーンを押し当てて超音波振動を与えることにより、中央上部の一部３２は圧縮されて薄肉部となる。この剥離部に幅が３．０ｍｍで厚みが０．１０ｍｍのニッケル金属製の舌状片からなる集電タブ３３を載置し、直径３．０ｍｍの銅製の溶接棒を用いて抵抗溶接を行った後、剥離部にポリプロピレン製テープを貼り付けて比較例２のニッケル正極板３０ａを作製する。
【００３３】
２．ニッケル−水素電池の作製
ａ．実施例１〜３のニッケル−水素電池
ついで、上述のように作製した各実施例のニッケル正極板１０ａ，１０ｂ，１０ｃを用いてニッケル−水素電池を作製する例を図４（なお、図４においてはニッケル正極板１０ａを用いた場合を示している）および図５に基づいて説明する。
上述のように作製した各ニッケル正極板１０ａ，１０ｂ，１０ｃと、水素吸蔵合金をパンチングメタル４１に塗布した負極板４０とをそれぞれポリプロピレン製不織布からなるセパレータ５０を介して、最外周が負極板４０となるようにして渦巻状に卷回してそれぞれ渦巻状電極体Ａを作製する。
【００３４】
一方、正極集電板６０はニッケル金属からなり、図５に示すように、この正極集電板６０は略円板状集電部６１と導出部６２とを備え、略円板状集電部６１は多数の開口６３を有するとともにこの集電部６１の中心線上に、即ち溶接時における一対の溶接電極を区画して配置するためのスリット６４が導出部６２まで延出して設けられている。略円板状集電部６１の中心部には電解液注液孔６５が設けられている。また、負極集電板７０はニッケル金属を円板状に形成して構成されるものである。
【００３５】
そして、上述のようにして作成した渦巻状電極体Ａの負極板４０の端部４１と負極集電板７０とを抵抗溶接するとともに、ニッケル正極板１０ａ，１０ｂ，１０ｃのリボン状パンチングメタル１３の端部と正極集電板６０の集電部６１とを抵抗溶接する。この抵抗溶接に際しては、まず、集電部６１に設けられたスリット６４を介して相対向させて一対の溶接電極（図示せず）を配置し、これらの一対の溶接電極間に溶接電流を流して抵抗溶接を行う。
【００３６】
ここで、一対の溶接電極間に溶接電流を流すと、活物質保持体１０の上端部はリボン状パンチングメタル１３の切断部の一部が突起状に活物質保持体１０より突出しているので、この突起状に突出した部分に溶接電流が集中し、突出した部分の一部は孔６３の周壁に固着する。これにより、リボン状パンチングメタル１３と正極集電板６０の略円板状集電部６１とが強固に固着されるようになる。
【００３７】
ついで、ＳＣサイズの有底円筒形の金属外装缶８０を用意し、上記のように各集電板６０，７０を溶接した渦巻状電極体Ａを金属外装缶８０内に挿入し、集電板６０の電解液注液孔６５より一方の溶接電極を挿入して負極集電板７０に当接させるとともに金属外装缶８０の底部に他方の溶接電極を当接して、負極集電板７０と金属外装缶８０の底部をスポット溶接する。
【００３８】
一方、正極キャップ９１と蓋体９２とからなる封口体９０を用意し、正極集電板６０の導出部６２を蓋体９２の底部に接触させて、蓋体９２の底部と導出部６２とを溶接して接続する。この後、金属外装缶８０内にそれぞれ３０重量％の水酸化カリウム（ＫＯＨ）水溶液よりなる電解液を注液し、封口体９０を封口ガスケット８２を介して外装缶８０の開口部８１に載置するとともに、この開口部８１を封口体９０側にカシメて封口する。これにより、公称容量２７００ｍＡＨの各実施例１〜３の円筒形ニッケル−水素蓄電池をそれぞれ作製する。
【００３９】
ｂ．比較例１のニッケル−水素蓄電池
ついで、上述のように作製した各比較例のニッケル正極板２０ａ，３０ａを用いてニッケル−水素電池を作製する例をそれぞれ説明する。まず、比較例１のニッケル正極板２０ａを用いる場合、上述と同様にニッケル正極板２０ａと水素吸蔵合金をパンチングメタル４１に塗布した負極板４０とをポリプロピレン製不織布からなるセパレータ５０を介して、最外周が負極板４０となるようにして渦巻状に卷回して渦巻状電極体Ａを作製する。
【００４０】
一方、上述した各実施例と同様な正極集電板６０と負極集電板７０とを用意し、渦巻状電極体Ａの負極板４０の端部４１と負極集電板７０とを抵抗溶接するとともに、ニッケル正極板２０ａのリボン状メタル２３の端部と正極集電板６０の略円板状集電部６１とを抵抗溶接する。この場合、リボン状メタル２３の端部には均等に溶接電流が流れるので、リボン状メタル２３と略円板状集電部６１とはそれほど強固には固着されない。
【００４１】
ついで、上述した各実施例と同様なＳＣサイズの有底円筒形の金属外装缶８０の底部と負極集電板７０とをスポット溶接した後、封口体９０の蓋体９２の底部と正極集電板６０の導出部６２とを溶接して接続する。この後、金属外装缶８０内に３０重量％の水酸化カリウム（ＫＯＨ）水溶液よりなる電解液を注液し、封口体９０を封口ガスケット８２を介して外装缶８０の開口部８１に載置するとともに、この開口部８１を封口体９０側にカシメて封口する。これにより、公称容量２７００ｍＡＨの比較例１の円筒形ニッケル−水素蓄電池を作製する。
【００４２】
ｃ．比較例２のニッケル−水素蓄電池
一方、ニッケル正極板３０ａを用いる場合、上述と同様にニッケル正極板３０ａと水素吸蔵合金をパンチングメタル４１に塗布した負極板４０とをそれぞれポリプロピレン製不織布からなるセパレータ５０を介して、最外周が負極板４０となるようにして渦巻状に卷回してそれぞれ渦巻状電極体Ａを作製する。
【００４３】
ついで、上述した各実施例と同様なＳＣサイズの有底円筒形の金属外装缶８０の底部と渦巻状電極体Ａの負極板４０の端部４１とを溶接した後、ニッケル正極板３０ａの舌片状集電タブ３３の端部と封口体９０の蓋体９２の底部とを溶接する。この後、金属外装缶８０内に３０重量％の水酸化カリウム（ＫＯＨ）水溶液よりなる電解液を注液し、封口体９０を封口ガスケット８２を介して外装缶８０の開口部８１に載置するとともに、この開口部８１を封口体９０側にカシメて封口する。これにより、公称容量３０００ｍＡＨの比較例２の円筒形ニッケル−水素蓄電池を作製する。
【００４４】
３．実験結果
ａ．不良率
このように作成した各円筒形ニッケル−水素蓄電池の巻き取り時から電池構成時までの不良率（内部短絡を生じたニッケル−水素蓄電池の個数の割合）を測定すると、下記の表１に示すような結果となった。
【００４５】
【表１】

【００４６】
上記表１より明らかなように、厚みを０．１０ｍｍとしたリボン状パンチングメタル１４を用いた実施例２のニッケル正極板１０ｂと、同様に厚みを０．１０ｍｍとした孔のないリボン状メタル２３を用いた比較例１のニッケル正極板２０ａとを比較すると、実施例２のニッケル正極板１０ｂは比較例１のニッケル正極板２０ａより不良率が半減することが分かる。これは、リボン状パンチングメタル１４を用いることにより、ニッケル正極板１０ｂの柔軟性が増し、渦巻状に巻回しても溶接部に剥がれが生じるのを防止できるようになったためである。
【００４７】
また、厚みを０．１８ｍｍとして厚みを厚くした実施例３のニッケル正極板１０ｃを用いても、これよりも厚みが薄い比較例１のニッケル正極板２０ａより不良率が低下することが分かる。このように、本発明においては、リボン状パンチングメタル１３，１４，１５を活物質保持体１０に溶接するようにしているので、孔のないリボン状メタル２３を用いるよりも不良率が低下する。
【００４８】
なお、上述した各実施例においては、円孔を設けたリボン状パンチングメタルを用いる例について説明したが、孔の形状としては円形以外に、三角形状、四角形状、五角形状などのどのような形状であっても同様な効果が得られる。また、パンチングメタルに代えてエキスパンドメタルを用いても同様な効果が得られる。
【００４９】
ｂ．電池容量および作動電圧
ついで、上述のようにして作製した各ニッケル−水素蓄電池を用いて放電特性を測定した。この測定においては、各ニッケル−水素蓄電池をそれぞれ１００％充電後、１０Ａの電流で放電させ、電池電圧が１．０Ｖになったときの放電時間から放電容量を測定する電池容量試験を行うと下記の表２に示すような結果となった。また、各ニッケル−水素蓄電池をそれぞれ１００％充電後、１０Ａの電流で放電させて、その作動電圧（開放状態から負荷を接続して１．００Ｖになるまでの中間の電圧値）を測定すると、下記の表２に示すような結果となった。
【００５０】
【表２】

【００５１】
上記表２より明らかなように、実施例１、実施例２および実施例３のニッケル正極板１０ａ，１０ｂ，１０ｃをそれぞれ用いたニッケル−水素蓄電池を比較すると、リボン状パンチングメタルの厚みをパンチングメタル１３→パンチングメタル１４→パンチングメタル１５と厚くすればするほど電池容量および作動電圧が向上することが分かる。これは、１０Ａというような大電流で放電させようとすると、リボン状パンチングメタルの厚みがパンチングメタル１５→パンチングメタル１４→パンチングメタル１３と薄くなればなるほど、リボン状パンチングメタルでの電圧降下が大きくなるためと考えられる。
【００５２】
また、比較例２のニッケル−水素蓄電池にあっては、放電容量が極端に低下するとともに、その作動電圧も低下した。これは、舌状片集電タブ３４を設けたのみでは、１０Ａというような大電流で放電させようとすると、集電タブ３４における電圧降下が大きすぎるものと考えられる。
【００５３】
さらに、実施例２のニッケル正極板１０ｂ（厚みが０．１０ｍｍのリボン状パンチングメタル１４を用いている）を用いたニッケル−水素蓄電池と、比較例１のニッケル正極板２０ａ（厚みが０．１０ｍｍの孔のないリボン状メタル２３を用いている）を用いたニッケル−水素蓄電池とは電池容量および作動電圧とも等しくなったが、孔のないリボン状メタル２３はこれ以上に厚みを厚くすると、ニッケル正極板２０ａの柔軟性がなくなるため、これ以上に厚みを厚くすることができない。一方、リボン状パンチングメタル１４を用いたニッケル正極板１０ｂは柔軟性があるため、リボン状パンチングメタルの厚みを厚くすることが可能となる。
【００５４】
上述したように、本実施形態においては、リボン状パンチングメタル１３，１４，１５は柔軟性を有するため、このような柔軟性を有するリボン状パンチングメタル１３，１４，１５を活物質未充填部分１２に溶着して渦巻状に巻回しても、リボン状パンチングメタル１３，１４，１５が破断するようなことはない。このため、電極体Ａ内に内部短絡を生ずることがなくなり、電極体Ａのリボン状パンチングメタル１３，１４，１５と正極集電板６０とが接続されて良好に集電できるようになって、電池容量および作動電圧が向上するとともに、大電流放電が可能なアルカリ蓄電池を得ることができるようになる。
【００５５】
なお、上述した実施形態においては、活物質未充填部分を形成する方法として超音波振動により活物質を剥離する例について説明したが、これに限らず、パンチングメタルの溶着部分に予め樹脂テープ等でマスキングを施し、活物質充填後にこのマスキングを取り除いてパンチングメタルを溶着するようにしても同様な効果が得られる。また、活物質を充填する前に発泡ニッケルとパンチングメタルとを溶着し、その後に活物質を充填するようにしても同様な効果が得られる。
【図面の簡単な説明】
【図１】本発明の一実施形態のパンチングメタルを発泡ニッケルからなる活物質保持体の活物質未充填部分に溶接した状態を示す図である。
【図２】従来例の金属製のリボンを発泡ニッケルからなる活物質保持体の活物質未充填部分に溶接した状態を示す図である。
【図３】他の従来例の舌片状の集電タブを発泡ニッケルからなる活物質保持体の活物質未充填部分に溶接した状態を示す図である。
【図４】図１の電極を渦巻状に巻回して形成した電極体を金属製の外装缶に収納して円筒状ニッケル−水素蓄電池として破断した状態を示す斜視図である。
【図５】正極集電板を示す斜視図である。
【符号の説明】
１０ａ，１０ｂ，１０ｃ…ニッケル正極、１０…発泡ニッケル（三次元的に網目構造をもった活物質保持体）、１１…活物質、１２…活物質未充填部分、１３，１４，１５…パンチングメタル（多孔性金属板）、４０…負極、５０…セパレータ、６０…円板状正極集電板、６１…集電部、６２…導出部、７０…円板状負極集電板、８０…円筒状金属製外装缶、８１…開口部、９０…封口体、９１…正極キャップ、９２…蓋体[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an alkaline storage battery such as a nickel / hydrogen storage battery, a nickel / cadmium storage battery, or a nickel / zinc storage battery.
[0002]
[Prior art]
Conventionally, electrodes used in alkaline storage batteries such as nickel / cadmium storage batteries, nickel / hydrogen storage batteries, nickel / zinc storage batteries, nickel salts on a sintered substrate formed by sintering nickel powder on a core body such as punching metal, A so-called sintered electrode is known which is impregnated with a solution such as a cadmium salt and is converted into an active material by alkali treatment. Since this sintered electrode has a low mechanical strength when the sintered substrate has a high porosity, it is practically limited to a porosity of about 80%, and a punching metal, etc. Since the core is required, there is a problem in realizing an electrode with a low packing density of the active material and a high energy density. In addition, since the pores of the sintered substrate are 10 μm or less, it is limited to solution impregnation methods and electrodeposition impregnation methods that require the active material filling process to be repeated many times. There is a problem that the cost becomes high.
[0003]
On the other hand, in order to improve these drawbacks, paste active material is directly applied to metal porous body (active material holding body) having a three-dimensional network structure such as metal fiber sintered body and foamed nickel (nickel sponge). Filled so-called non-sintered electrodes have become mainstream. Since this kind of porous metal body having a three-dimensional network structure has a high porosity of about 95%, the active material can be filled with high density. Therefore, a high-capacity battery can be obtained, and this type of non-sintered electrode fills the metal porous body with the active material as it is, which eliminates the need for troublesome active material treatment and facilitates manufacture. There is an advantage of becoming.
[0004]
By the way, in this kind of non-sintered electrode, since the porous metal body having a three-dimensional network structure does not have a core body, an electrode formed by filling the porous metal body with an active material and Various proposals have been made for conductive connection between battery terminals. For example, in Japanese Patent Application Laid-Open No. 61-218067, when manufacturing an electrode using a metal fiber felt-like sintered body (metal fiber sintered body) as an electrode support, a metal fiber felt-like body and a net-like body are used. It has been proposed to integrally form a conductive auxiliary body made of punching metal, wire rod, flat plate, etc. by sintering to improve the mechanical strength of the metal-fiber felt-like body and improve the current collecting property. It was.
[0005]
However, the metal fiber sintered body is formed in a long shape by bundling thin metal fibers (for example, a line diameter of 10 μm) in the length direction of the electrode, and therefore an active material is applied to the metal fiber sintered body. After that, when the positive and negative electrodes are wound spirally through the separator, thin metal fibers are cut during winding, and the cut fiber pieces break through the separator and the positive and negative electrodes are electrically connected. This causes a problem that an internal short circuit occurs.
[0006]
On the other hand, in an electrode using nickel foam as an electrode support, even after an active material is applied to nickel foam, the nickel foam itself is cut even if the positive and negative electrodes are wound spirally through a separator. Absent. However, in order to collect current from the electrode, a part of the active material of the electrode is peeled to expose the foamed nickel, and a tongue-like current collecting tab is welded to the exposed portion. For this reason, since the current collecting property at the tongue-shaped current collecting tab is not good, a problem arises that a voltage drop occurs at the current collecting tab when large current discharge is performed.
[0007]
Therefore, in Japanese Patent Application Laid-Open No. 62-139251, an end portion of an electrode using foamed nickel as an electrode support is compressed in the width direction to form a dense layer, and the compressed dense layer and the electrode surface are perpendicular to each other. A so-called tabless type battery in which the arranged disk-shaped lead pieces are welded has been proposed. In the electrode proposed in Japanese Patent Laid-Open No. Sho 62-139251, since the foam metal is used as an electrode support, the foam metal itself is not cut even if it is wound in a spiral shape. Since the end of each and the disc-shaped lead piece are welded, the current collecting property is improved.
[0008]
[Problems to be solved by the invention]
However, in the electrode proposed in Japanese Patent Application Laid-Open No. 62-139251, the dense layer formed by compressing the end of the electrode in the width direction is inferior in flexibility. When winding the film, a part of the dense layer breaks to generate burrs, which causes a problem that the burrs break through the separator and cause an internal short circuit. In addition, if a flexible part and a non-flexible part are mixed in the electrode as a whole, it is difficult to wind the positive and negative electrodes with uniform pressure. The problem of not being done also arises.
[0009]
It is also conceivable to form an unfilled portion of the active material on one end face of the electrode support made of foamed nickel, and weld a ribbon-like metal plate to the unfilled portion of the active material. However, when the electrode and the counter electrode formed in this manner are wound in a spiral shape via a separator, the ribbon-shaped metal plate does not have flexibility, so that a part of the ribbon-shaped metal plate becomes a square shape. A problem arises in that it bends and contacts the counter electrode to cause an internal short circuit.
[0010]
The object of the present invention is to eliminate the above-mentioned problem, and even if a metal porous body having a three-dimensional network structure is used as an active material holding body and wound in a spiral shape, it does not cause an internal short circuit. The object is to obtain an electrode body capable of collecting current.
[0011]
[Means for solving the problems and their functions and effects]
In order to achieve the above-mentioned object, the present invention comprises a non-consolidated electrode on one electrode and an electrode on the other electrode, each holding a paste-like active material on an active material holder made of foamed nickel and having a three-dimensional network structure. The electrode body wound in a spiral shape via a separator also serves as the terminal of the other electrode in a state where the substantially disk-shaped current collector of the current collector is connected to the upper side of the non-consolidated electrode of the one electrode A paste-like active material which is a cylindrical alkaline storage battery housed in a cylindrical metal outer can, the upper side of the non-consolidated electrode connected to the substantially disk-shaped current collector of the current collector held on the surface thereof The active material unfilled portions formed by thinning by compression and compressed, and the holes having a diameter of 0.30-1.00 mm welded to the surface of the active material unfilled portions are staggered every line. A number of porous metal plates that are formed in the hole and projecting into the cutting site There is provided a cylindrical alkaline storage battery using a non-sintered electrode, characterized in that welded to the substantially disc-shaped current collecting portion of the current collector at the cut end face.
[0012]
Since the porous metal plate has flexibility, the porous metal plate is broken even if the porous metal plate having such flexibility is welded to the unfilled portion of the active material and wound in a spiral shape. There is no such thing. For this reason, an internal short circuit does not occur in the electrode body, and the porous metal plate of the electrode body and the substantially disk-shaped current collector are connected so that current can be collected favorably, enabling large current discharge. An alkaline storage battery can be obtained. When the active material holding body having a three-dimensional network structure is made of foamed nickel, the foamed nickel has flexibility, so that the foamed nickel itself is not cut even when it is wound in a spiral shape. For this reason, it is possible to obtain an alkaline storage battery with good current collection and large capacity without causing an internal short circuit in the electrode body.
[0013]
In addition, if punching metal or expanded metal is used as the porous metal plate, these punching metal or expanded metal has sufficient flexibility, so that even if it is wound in a spiral shape, the punching metal or expanded metal is broken. There is nothing to do. In addition, when the punching metal or the expanded metal is cut at the center of the hole, and the cut portion is welded to the substantially disk-shaped current collector, the cut portion is in contact with the substantially disk-shaped current collector. Therefore, when resistance welding is performed, the current density of the portion in contact with the protrusion increases and becomes firmly fixed.
[0019]
DETAILED DESCRIPTION OF THE INVENTION
Below, one Embodiment at the time of applying the cylindrical alkaline storage battery using the non-sintered electrode of this invention to a nickel-hydrogen storage battery is described based on figures.
1 is a view showing a state in which the porous metal plate of this embodiment is welded to an active material unfilled portion of an active material holder made of nickel foam, and FIG. 2 is a metal plate of a comparative example (conventional example). FIG. 3 is a view showing a state where (ribbon) is welded to an active material unfilled portion of an active material holder made of foamed nickel, and FIG. 3 shows a tongue-shaped current collecting tab of another comparative example (conventional example) FIG. 4 is a view showing a state where the active material holding body is welded to an unfilled portion of the active material, and FIG. 4 is a state in which the electrode body formed by winding the electrode of FIG. FIG. 5 is a perspective view showing a positive electrode current collector plate.
[0020]
1. Preparation of nickel positive electrode plate a. Example 1
90 parts by weight of nickel hydroxide, 5 parts by weight of metallic cobalt powder and 5 parts by weight of cobalt hydroxide powder are mixed and kneaded with 20 parts by weight of a 1% by weight aqueous solution of methylcellulose to produce a paste-like active material. . Such a paste active material 11 prepared in the, substrate basis weight is 600 g / m ² (Note that the substrate basis weight can be used is between 400~700g / m ²⁾ nickel foam is 1.5mm and a thickness An active material holder 10 made of a body (nickel sponge) is filled. The active material filling density after rolling is filled with a paste-like active material so as to be about 2.9 to 3.05 g / cc-void. Next, after the active material holder 10 filled with the paste-like active material 11 is dried, it is rolled until the thickness becomes about 0.7 mm.
[0021]
Next, an ultrasonic horn (not shown) is pressed against the upper side portion 12 of the active material holding body 10 filled with the pasty active material 11 in this manner, and ultrasonic vibration is applied to the upper side portion 12 in the vertical direction to hold the active material. The active material 11 filled in the upper side portion 12 of the body 10 is dropped from the active material holding body 10 to form a peeling portion. At this time, by applying an ultrasonic vibration by pressing the ultrasonic horn, the upper side portion 12 is compressed into a thin portion.
[0022]
On the other hand, as shown in FIG. 1, as a porous metal plate, a plurality of circular holes having a thickness of 0.06 mm and a hole diameter of 0.30 to 1.00 mm are formed so as to be staggered every line, and the porosity is increased. The ribbon-like punching metal 13 made of nickel metal formed so as to be 20 to 60% is used. The ribbon punching metal 13 made of nickel metal is cut at the center of the circular hole so as to have a width of 1.5 mm.
[0023]
The nickel metal ribbon-like punching metal 13 is placed on the peeling portion of the active material holder 10 so that the cut portion cut at the center of the circular hole slightly protrudes from the upper end of the active material holder 10. Then, resistance welding is performed at intervals of 2 mm using a copper welding rod having a diameter of 1.5 mm to produce the nickel positive electrode plate 10a of Example 1. As a result, a part of the cut portion of the punching metal 13 protrudes from the active material holding body 10 in a protruding shape at the upper end portion of the active material holding body 10.
[0024]
b. Example 2
After the pasty active material 11 prepared in the same manner as in Example 1 is filled in the active material holder 10 similar to that in Example 1, an ultrasonic horn (not shown) is pressed against the upper side portion 12 of the active material holder 10. Then, ultrasonic vibration is applied to the upper side portion 12 in the vertical direction, and the active material 11 filled in the upper side portion 12 of the active material holding body 10 is dropped from the active material holding body 10 to form a peeling portion. At this time, by applying an ultrasonic vibration by pressing the ultrasonic horn, the upper side portion 12 is compressed into a thin portion.
[0025]
On the other hand, as shown in FIG. 1, as a porous metal plate, a plurality of circular holes having a thickness of 0.10 mm and a hole diameter of 0.30 to 1.00 mm are formed so as to be staggered every line, and the porosity is increased. The ribbon-like punching metal 14 made of nickel metal formed so as to be 20 to 60% is used. The ribbon punching metal 14 made of nickel metal is cut at the center of the hole so as to have a width of 1.5 mm.
[0026]
The nickel metal ribbon-like punching metal 14 is placed on the peeling portion of the active material holder 10 so that the cut portion cut at the center of the circular hole slightly protrudes from the upper end of the active material holder 10. Then, resistance welding is performed at intervals of 2 mm using a copper welding rod having a diameter of 1.5 mm, and the nickel positive electrode plate 10b of Example 2 is manufactured. As a result, a part of the cut portion of the punching metal 14 protrudes from the active material holding body 10 in a protruding shape at the upper end portion of the active material holding body 10.
[0027]
c. Example 3
After the pasty active material 11 prepared in the same manner as in Example 1 is filled in the active material holder 10 similar to that in Example 1, an ultrasonic horn (not shown) is pressed against the upper side portion 12 of the active material holder 10. Then, ultrasonic vibration is applied to the upper side portion 12 in the vertical direction, and the active material 11 filled in the upper side portion 12 of the active material holding body 10 is dropped from the active material holding body 10 to form a peeling portion. At this time, by applying an ultrasonic vibration by pressing the ultrasonic horn, the upper side portion 12 is compressed into a thin portion.
[0028]
On the other hand, as shown in FIG. 1, the porous metal plate has a thickness of 0.18 mm and a large number of holes having a hole diameter of 0.30 to 1.00 mm formed alternately in each row. The ribbon-like punching metal 15 made of nickel metal formed so as to be 20 to 60% is used. The ribbon punching metal 15 made of nickel metal is cut at the center of the circular hole so that the width is 1.5 mm.
[0029]
The nickel metal ribbon-like punching metal 15 is placed on the peeling portion of the active material holding body 10 so that the cut portion cut at the center of the circular hole slightly protrudes from the upper end portion of the active material holding body 10. Then, resistance welding is performed at intervals of 2 mm using a copper welding rod having a diameter of 1.5 mm to produce the nickel positive electrode plate 10c of Example 3. As a result, a part of the cut portion of the punching metal 15 protrudes from the active material holding body 10 in a protruding shape at the upper end portion of the active material holding body 10.
[0030]
d. Comparative Example 1
As shown in FIG. 2, the pasty active material 21 prepared in the same manner as in Example 1 is filled in the active material holder 20 similar to that in Example 1, and then illustrated on the upper side 22 of the active material holder 20. The ultrasonic horn that is not pressed is pressed, ultrasonic vibration is applied in the vertical direction to the upper side portion 22, and the active material 21 filled in the upper side portion 22 of the active material holding body 20 is detached from the active material holding body 20 and peeled off. Forming part. At this time, by applying ultrasonic vibration by pressing the ultrasonic horn, the upper side portion 22 is compressed into a thin portion.
[0031]
On the other hand, as shown in FIG. 2, as the metal plate, a nickel metal plate (ribbon metal) 23 cut to have a thickness of 0.10 mm and a width of 1.5 mm is prepared. A ribbon-like metal 23 made of metal is placed on the peeled portion of the active material holder 20, and resistance welding is performed at intervals of 2 mm using a copper welding rod having a diameter of 1.5 mm to produce a nickel positive electrode plate 20a of Comparative Example 1. To do.
[0032]
e. Comparative Example 2
As shown in FIG. 3, after the pasty active material 31 prepared in the same manner as in Example 1 is filled into the active material holder 30 similar to that in Example 1, a part of the center upper portion of the active material holder 30 is filled. An ultrasonic horn having the same width as that of the part 32 is pressed against the part 32 to apply ultrasonic vibration in the vertical direction to the upper part of the center, and the active material 31 filled in the part 32 at the upper part of the center of the active material holder 30. Is removed from the active material holder 30 to form a peeling portion. At this time, by applying ultrasonic vibration by pressing the ultrasonic horn, a part 32 at the center upper portion is compressed into a thin-walled portion. A current collecting tab 33 made of a nickel metal tongue-shaped piece having a width of 3.0 mm and a thickness of 0.10 mm is placed on the peeling portion, and resistance welding is performed using a copper welding rod having a diameter of 3.0 mm. After that, a nickel-made positive electrode plate 30a of Comparative Example 2 is manufactured by attaching a polypropylene tape to the peeling portion.
[0033]
2. Preparation of nickel-hydrogen battery a. Next, an example in which a nickel-hydrogen battery is manufactured using the nickel

positive electrode plates

10a, 10b, and 10c of each of the examples manufactured as described above is shown in FIG. Is a case where the nickel positive electrode plate 10a is used) and FIG.
Each of the nickel

positive plates

10a, 10b, and 10c produced as described above and the negative plate 40 in which a hydrogen storage alloy is applied to the punching metal 41 are connected to each other through the separator 50 made of polypropylene nonwoven fabric, and the outermost periphery is the negative plate 40. Thus, the spiral electrode body A is produced by winding in a spiral shape.
[0034]
On the other hand, the positive electrode current collector plate 60 is made of nickel metal, and as shown in FIG. 5, the positive electrode current collector plate 60 includes a substantially disk-shaped current collector portion 61 and a lead-out portion 62. 61 has a large number of openings 63 and a slit 64 for partitioning and arranging a pair of welding electrodes at the time of welding is provided on the center line of the current collecting portion 61 so as to extend to the lead-out portion 62. An electrolyte injection hole 65 is provided at the center of the substantially disc-shaped current collector 61. The negative electrode current collector plate 70 is configured by forming nickel metal into a disk shape.
[0035]
The end 41 of the negative electrode plate 40 of the spiral electrode body A prepared as described above and the negative electrode current collector plate 70 are resistance-welded, and the ribbon-like punching metal 13 of the nickel

positive electrode plates

10a, 10b, and 10c. The end and the current collector 61 of the positive electrode current collector plate 60 are resistance welded. In this resistance welding, first, a pair of welding electrodes (not shown) are arranged to face each other through a slit 64 provided in the current collector 61, and a welding current is passed between the pair of welding electrodes. Resistance welding.
[0036]
Here, when a welding current is passed between the pair of welding electrodes, the upper end portion of the active material holding body 10 protrudes partly from the active material holding body 10 in a protruding shape from the cut portion of the ribbon-like punching metal 13. The welding current concentrates on the protruding portion, and a part of the protruding portion is fixed to the peripheral wall of the hole 63. As a result, the ribbon-shaped punching metal 13 and the substantially disk-shaped current collecting portion 61 of the positive electrode current collecting plate 60 are firmly fixed.
[0037]
Next, an SC size bottomed cylindrical metal outer can 80 is prepared, and the spiral electrode body A welded to each of the

current collector plates

60 and 70 is inserted into the metal outer can 80 as described above. One welding electrode is inserted from the electrolyte solution injection hole 65 and brought into contact with the negative electrode current collector plate 70, and the other welding electrode is brought into contact with the bottom of the metal outer can 80, so that the negative electrode current collector plate 70 and the metal are brought into contact with each other. The bottom of the outer can 80 is spot welded.
[0038]
On the other hand, a sealing body 90 composed of a positive electrode cap 91 and a lid body 92 is prepared, and the outlet portion 62 of the positive electrode current collector plate 60 is brought into contact with the bottom portion of the lid body 92 so that the bottom portion of the lid body 92 and the outlet portion 62 are Weld and connect. Thereafter, an electrolytic solution made of a 30 wt% potassium hydroxide (KOH) aqueous solution is poured into the metal outer can 80, and the sealing body 90 is placed on the opening 81 of the outer can 80 via the sealing gasket 82. At the same time, the opening 81 is crimped to the sealing body 90 side and sealed. Thereby, the cylindrical nickel-hydrogen storage battery of each Examples 1-3 of nominal capacity 2700mAH is produced, respectively.
[0039]
b. Next, an example in which a nickel-hydrogen battery is manufactured using the nickel

positive electrode plates

20a and 30a of each comparative example manufactured as described above will be described. First, when the nickel positive electrode plate 20a of Comparative Example 1 is used, the nickel positive electrode plate 20a and the negative electrode plate 40 in which the hydrogen storage alloy is applied to the punching metal 41 are connected to each other through the separator 50 made of polypropylene nonwoven fabric in the same manner as described above. A spiral electrode body A is produced by winding in a spiral shape so that the outer periphery becomes the negative electrode plate 40.
[0040]
On the other hand, the same positive electrode current collector plate 60 and negative electrode current collector plate 70 as those in the above-described embodiments are prepared, and the end 41 of the negative electrode plate 40 of the spiral electrode body A and the negative electrode current collector plate 70 are resistance-welded. At the same time, the end of the ribbon-like metal 23 of the nickel positive electrode plate 20 a and the substantially disk-shaped current collector 61 of the positive electrode current collector plate 60 are resistance-welded. In this case, since the welding current flows evenly at the end of the ribbon-shaped metal 23, the ribbon-shaped metal 23 and the substantially disk-shaped current collector 61 are not firmly fixed.
[0041]
Next, after spot welding the bottom portion of the SC-shaped bottomed cylindrical metal outer can 80 and the negative electrode current collector plate 70 as in the above-described embodiments, the bottom portion of the lid 92 of the sealing body 90 and the positive electrode current collector The lead-out portion 62 of the plate 60 is connected by welding. Thereafter, an electrolytic solution made of 30 wt% potassium hydroxide (KOH) aqueous solution is poured into the metal outer can 80, and the sealing body 90 is placed on the opening 81 of the outer can 80 via the sealing gasket 82. At the same time, the opening 81 is crimped to the sealing body 90 side and sealed. This produces the cylindrical nickel-hydrogen storage battery of Comparative Example 1 having a nominal capacity of 2700 mAH.
[0042]
c. On the other hand, in the case of using the nickel positive electrode 30a of the nickel-hydrogen storage battery of Comparative Example 2, the separator 50 made of a nonwoven fabric made of polypropylene is used for each of the nickel positive electrode 30a and the negative electrode 40 coated with the hydrogen storage alloy 41 on the punching metal 41 as described above. Then, the spirally wound electrode body A is produced by winding it in a spiral shape so that the outermost periphery is the negative electrode plate 40.
[0043]
Next, after welding the bottom part of the SC-shaped bottomed cylindrical metal outer can 80 and the end part 41 of the negative electrode plate 40 of the spiral electrode body A similar to the above-described embodiments, the tongue of the nickel positive electrode plate 30a is welded. The end of the strip-like current collecting tab 33 and the bottom of the lid 92 of the sealing body 90 are welded. Thereafter, an electrolytic solution made of 30 wt% potassium hydroxide (KOH) aqueous solution is poured into the metal outer can 80, and the sealing body 90 is placed on the opening 81 of the outer can 80 via the sealing gasket 82. At the same time, the opening 81 is crimped to the sealing body 90 side and sealed. Thereby, the cylindrical nickel-hydrogen storage battery of the comparative example 2 with a nominal capacity of 3000 mAH is produced.
[0044]
3. Experimental results a. Defective rate When the defective rate (ratio of the number of nickel-hydrogen storage batteries that caused an internal short-circuit) from the winding of each cylindrical nickel-hydrogen storage battery thus created to the time of battery configuration was measured, the following Table 1 was obtained. The result was as shown.
[0045]
[Table 1]

[0046]
As apparent from Table 1 above, the nickel positive electrode plate 10b of Example 2 using the ribbon-like punching metal 14 having a thickness of 0.10 mm, and the ribbon-like metal 23 having no hole and having a thickness of 0.10 mm. When compared with the nickel positive electrode plate 20a of Comparative Example 1 using the above, it can be seen that the nickel positive electrode plate 10b of Example 2 has a defective rate halved compared to the nickel positive electrode plate 20a of Comparative Example 1. This is because the use of the ribbon-shaped punching metal 14 increases the flexibility of the nickel positive electrode plate 10b and prevents the weld from peeling off even if it is wound in a spiral shape.
[0047]
Moreover, even if it uses the nickel positive electrode plate 10c of Example 3 which made thickness 0.18 mm thick, it turns out that a defect rate falls rather than the nickel positive electrode plate 20a of the comparative example 1 whose thickness is thinner than this. Thus, in the present invention, since the ribbon-like punching metals 13, 14, 15 are welded to the active material holder 10, the defect rate is lower than when the ribbon-like metal 23 without holes is used.
[0048]
In each of the above-described embodiments, an example in which a ribbon-shaped punching metal provided with a circular hole is used has been described. However, the shape of the hole is not limited to a circle, but can be any shape such as a triangle, a quadrangle, or a pentagon. However, the same effect can be obtained. The same effect can be obtained by using expanded metal instead of punching metal.
[0049]
b. Battery capacity and operating voltage Next, discharge characteristics were measured using each nickel-hydrogen storage battery produced as described above. In this measurement, each nickel-hydrogen storage battery was 100% charged, discharged at a current of 10 A, and subjected to a battery capacity test in which the discharge capacity was measured from the discharge time when the battery voltage reached 1.0 V. The results shown in Table 2 were obtained. Moreover, after each nickel-hydrogen storage battery is 100% charged and discharged at a current of 10 A, the operating voltage (intermediate voltage value from the open state to 1.00 V when the load is connected) is measured. The results shown in Table 2 below were obtained.
[0050]
[Table 2]

[0051]
As apparent from Table 2 above, when the nickel-hydrogen storage batteries using the nickel

positive plates

10a, 10b and 10c of Examples 1, 2 and 3 are compared, the thickness of the ribbon-like punching metal is compared with the punching metal. It can be seen that the battery capacity and the operating voltage are improved as the thickness is increased from 13 to punching metal 14 to punching metal 15. This is because when the discharge is performed with a large current of 10 A, the voltage drop at the ribbon-shaped punching metal becomes larger as the thickness of the ribbon-shaped punching metal becomes thinner as the punching metal 15 → the punching metal 14 → the punching metal 13. It is thought to be.
[0052]
Moreover, in the nickel-hydrogen storage battery of Comparative Example 2, the discharge capacity was extremely reduced and the operating voltage was also reduced. It is considered that the voltage drop at the current collecting tab 34 is too large if the tongue-shaped piece current collecting tab 34 is provided only when discharging with a large current of 10A.
[0053]
Furthermore, a nickel-hydrogen storage battery using the nickel positive electrode plate 10b of Example 2 (using a ribbon-like punching metal 14 having a thickness of 0.10 mm) and a nickel positive electrode plate 20a of Comparative Example 1 (thickness of 0.10 mm). The battery capacity and the operating voltage are equal to those of the nickel-hydrogen storage battery using the ribbon-like metal 23 having no holes), but if the ribbon-like metal 23 having no holes is made thicker than this, the nickel-hydrogen storage battery Since the flexibility of the positive electrode plate 20a is lost, the thickness cannot be increased further. On the other hand, since the nickel positive electrode plate 10b using the ribbon-like punching metal 14 is flexible, the thickness of the ribbon-like punching metal can be increased.
[0054]
As described above, in the present embodiment, since the ribbon-shaped punching metals 13, 14, and 15 have flexibility, the ribbon-shaped punching metals 13, 14, and 15 having such flexibility are used as the active material unfilled portion 12. The ribbon-like punching metals 13, 14, and 15 are not broken even if they are welded to each other and wound in a spiral shape. For this reason, an internal short circuit does not occur in the electrode body A, and the ribbon-like punching metals 13, 14, 15 of the electrode body A and the positive electrode current collector plate 60 are connected and can collect current well. The battery capacity and operating voltage are improved, and an alkaline storage battery capable of discharging a large current can be obtained.
[0055]
In the above-described embodiment, an example in which the active material is peeled off by ultrasonic vibration has been described as a method for forming the active material unfilled portion. The same effect can be obtained by performing masking, removing the masking after filling the active material, and welding the punching metal. Further, the same effect can be obtained by welding the foamed nickel and the punching metal before filling the active material and filling the active material after that.
[Brief description of the drawings]
FIG. 1 is a view showing a state where a punching metal according to an embodiment of the present invention is welded to an active material unfilled portion of an active material holder made of foamed nickel.
FIG. 2 is a view showing a state in which a metal ribbon of a conventional example is welded to an active material unfilled portion of an active material holder made of foamed nickel.
FIG. 3 is a view showing a state in which a tongue-shaped current collecting tab of another conventional example is welded to an active material unfilled portion of an active material holder made of nickel foam.
4 is a perspective view showing a state in which an electrode body formed by winding the electrode of FIG. 1 in a spiral shape is housed in a metal outer can and broken as a cylindrical nickel-hydrogen storage battery. FIG.
FIG. 5 is a perspective view showing a positive electrode current collector plate.
[Explanation of symbols]
10a, 10b, 10c ... nickel positive electrode, 10 ... nickel foam (active material holder having a three-dimensional network structure), 11 ... active material, 12 ... active material unfilled portion, 13, 14, 15 ... punching metal (Porous metal plate), 40 ... negative electrode, 50 ... separator, 60 ... disc-shaped positive current collector, 61 ... current collector, 62 ... lead-out portion, 70 ... disc-shaped negative current collector, 80 ... cylindrical Metal outer can, 81 ... opening, 90 ... sealing body, 91 ... positive electrode cap, 92 ... lid

Claims

An electrode body obtained by winding a non-consolidated electrode on one electrode holding a paste-like active material and an electrode on the other electrode in a spiral shape through a separator on an active material holder made of nickel foam and having a three-dimensional network structure Is stored in a cylindrical metal outer can also serving as a terminal of the other electrode in a state where a substantially disk-shaped current collector of the current collector is connected to the upper side of the non-consolidated electrode of the one electrode Because
An active material unfilled portion formed by compressing the upper active portion of the non-contaminated electrode connected to the substantially disk-shaped current collector of the current collector by peeling off the paste-like active material held on the surface thereof Each of the porous metal plates projecting to the cutting site is formed by forming a large number of holes having a diameter of 0.30 to 1.00 mm welded to the surface of the unfilled portion of the active material so as to be alternated every line. A cylindrical alkaline storage battery using a non-sintered electrode characterized in that it is welded to a substantially disk-shaped current collector of the current collector at the cut end face of the hole.

The porous metal plate is a ribbon-like punching metal or expanded metal having a porosity of 20-60% in which a large number of holes having a hole diameter of 0.30-1.00 mm are formed alternately in each row. 2. A cylindrical alkaline storage battery using the non-sintered electrode according to claim 1.